Flame resistant organic textiles and method of production



Uni St e P t n I Agriculture No-Drawing; Original application l'uneigI956, Serial No; 589,562; Divided and this application April 24,- I'957,.SeriaLNo;. 661,551

8 Claims. 01. 117:1

(Grantedi under Title 35, US. Codev (-1952); sec.- 266) A non-exclusive,irrevocable, royalty-free licenseinthe. invention herein described,throughout the world for. all purposes ofithe United StatesGovernment,with thepower.

to grant suhlicenseslfor such purposes, is, hereby grantedv L to. the.Government of the United StatesofAmerica.

This invention relates to flame resistantorganic textile. fabrics and totheir production by. treating, the. fabrics withitl'le novel polymersdisclosed. and claiinedinSer. No.. 589,562, filed; June. 5, 1956,. nowPatent No.. 2,886,539,, o which the. present application is. adivision.

In. general,, this inventionv relates to theproduction of. flame prooftextiles by the use of polymers capable. of beingproduced by thereaction of a L-aziridinyl phosphine oxide or sulfide (.e.g. a compoundthat contains at least one l -aziridinyl' group,

6H, -fN

. C attached. to pentavalent phosphorus), with a. methylol phosphoruscompoundoflthe formula. I

RGHa(CHzOH)r am uncmhr'r moflmr wherein A represents. a monovalent.anion and R repre- SentsJOH or a radical producedby'the reaction-oftheOH. of a PCH OH group with a nitrogen compound contain! ing at least onetrivalent nitrogen atom. and at. least one; member selectedv from thegroup consisting of. H. and. CH OH attached to trivalent nitrogen atoms.

Methods. for producing reaction products of the. methylol phosphoruscompounds with. the. trivalent. nitrogen compounds are disclosedinPatenLNumbers 2,772,- 188, 2,809,941, and 2,812,311. J

Other aziridiny-l compoundsthatundergo. reactions described hereinconsist of compounds. or polymers con taining the following structures:A

ICC

We have discovered that compounds that contain at least one l-aziridinylgroup attached to pentavalent phosphorusatoms react with methylolphosphoms compounds (ezg. compounds that containat least' two HOCHQPgroups)" to produce polymers. Suchpolymers contain the-reoccurringconnecting'striictures,

and

P I -'CH2CH2OCH2P wherein the phosphorus atoms are pentavalent.

Such' polymers can. be produced in the form of solid' 5 syntheticresins. They can. be deposited onthe surfaces.

and/or in the interstices. of hydrophilic fibrous organic materials,i.e., organicmaterials which. absorber adsorb.

' valent phosphorus atoms.

water. When such resins are deposited, they reduce the comhustibil'ityof hydrophilic fibrous organic materials and resist removal bylaundering and the like chemical;

treatments. Such resins can be deposited on the. surfaces. of".non-hydrophilic materials. to form flame resistant;

coatings.

' l az iridinyl phosphineoxides or sulfidessuitablefor use. in" thisinvention arev compounds whichcontain. at least one l-aziridinyl group,(CH N-,. attached to. penta The compounds used in this invention may berepresented by the following structure::

- processes. for producing such: compounds;

andwhereZl isoxygen or sulfur. The aziridinyl compoundsrcan bepreparedby substantially'any of the'known- In general}, they are. prepared byreacting ethylenimine with the. corresponding phosphorushalide..Thepreparation ofi tris(,l -aziridinyl)phosphine oxide, [(CH N-] P0, hasbeen described-by Bestian and coworkers [Bestian et al., Ann; 566',210-244 (1950).].v I Suitable methylol. phosphorus compounds includetris, hydroxymethyl)phosphine oxide; a phosphoniurn salt of the formula[(HOCH P1+A inv which A represents a monovalent anion; and the productsof reacting either the phosphine oxide or the phosphonium salt with aMethyloll Reacting compound ('i.e. a compound capable of' reactingwitha" PCHQOH group) to produce a derivative that retains at least twoPCH OH groups. The phosphonium chloride;tetrakis(hydroxymethybphosphonium chloride; of the formula (HOCH PCl, isa readily obtainable phosphonium' salt, andis the preferred salt for 1;togandemployed in the' form of, for: example: thephos- Patented. Nov. 3,a.

phoniumacetate (HOCH POAc; the phosphonium dihydrogen phosphate or thelike phosphonium salt. The methylol phosphorus group containingderivatives of the phosphine oxide or the phosphonium salt can be asubstantially monomeric prod- I uct of reacting the phosphorus compoundwith at least one methylol reacting compound which is monofunctional inits capacity to react with PCH OH groups, so. that from about 1 to 2moles of the methylol reacting compound combines with each mole of thephosphorus compound. Illustrative examples include the products of soreacting the tris(hydr oxymethyl)phosphine oxide and/or the phosphoniumsalt with at least one: secondary amines such. as diethylamine, N-vinylcyclohexylamine, or the like; N-substituted amides such as N-methylacrylamide, N-N'-tri nethyl pinic acid diamide, N-propyl benzamide andthe like; acids such as 'stearic acid, pinonic acid, monobutylphthalate, and the like; and the like monofunctional reactants. Themethylol phosphorus containing derivative can be a further polymerizablemethylol phosphorus polymer such as water soluble polymers formed byreacting tetrakis(hydroxymethyl) phosphonium chloride with melamine orwith methylated methylolmelamine such as those described in copendingpatent application Serial No. 421,213, filed April 5, 1954, now PatentNo. 2,812,311.

' Polymers provided by this invention can be produced in acidic,neutral, and alkaline conditions. They can be produced in the form ofliquids or solids and can be molded by the conventionaltechniques ofmolding thermosetting resins. These polymers are valuable materials foruse in production of: molded synthetic articles, such as buttons,electrical insulators and the like; synthetic coatings such asprotective coatings, and paints and the like having reducedflammability; paper treating resins; textile resins; and the like.

The polymers provided by this invention are preferably prepared bygently heating a solution of the aziridinyl phosphine oxide or sulfideand the methylol phosphonium or methylol phosphine oxide untilpolymerization occurs. The preferred relative amounts of aziridinylcompound and methylol phosphonium or phosphine oxide used to polymerizecan be calculated by conventional methods by assuming that: (1) for eachaziridinyl group present in the compound, the functionality is two (e.g.if two aziridinyl groups are present, the functionality is four), (2)that the functionality of the methylol phosphorus compound is equal tothe number of methylol groups present in the compound, (3) thattetrakis(hydroxymethyl)phosphonium chloride is converted totris(hydroxymethyDphosphine oxide in the presence of neutral carbonateslike calcium carbonate, alkali carbonates like sodium carbonate, alkalimetal hydroxides, .tertiary amines, and bases in general. Thus it isapparent that in the preferred relative proportions, the aziridinylcompound and the methylol phosphorus compound will be present in suchamounts that one aziridinyl group is provided for two methylol groups.

I The polymers of this invention can be modified by incorporating analkyl amine or an aliphatic alcohol into the solution containing theaziridinyl compound and the methylol phosphorus compound. For example ifcetyl alcohol is used the polymers are especially suited for use in theproduction of soft, flame-resistant textiles.

I The combustibility of organic fibrous materials can be reduced inaccordance with this invention by: impregnating the fibrous materialswith an aqueous solution, or uniform suspension or dispersion, of themonomeric compounds, or the partially polymerized monomers formed byreacting the monomeric compounds until partial poly 4 merization occurs;and curing the impregnated materials at the temperatures conventionallyused for curing fibrous organic materials.

When tetrakis(hydroxymethyl)phosphonium chloride is the methylolphosphorus, compound used, it is preferable to dissolve it in waterfirst, then add sufiicient basic reacting compound toraise the pH of theaqueous solution to about 5 to 7 before adding the aziridinyl compound.

I The pH of the solution containing the methylol phos-. phoruscompound'and the aziridinyl compound greatly influences'the nature ofthe resulting polymer. The pH of these solutions can be adjusted withsubstantially any acid or base reacting material. Suitable acids includehy-" drochloric andacetic. Suitable bases include sodium hydroxide,sodium bicarbonate, sodium carbonate, tnethanolamine and ethanolamine.If the pH of the solution is less than about 55, polymerization oftenproceeds so rapidly when heated that suflicien-t heat is produced fromthe exothermic reaction to cause the product to decompose with evolutionof white fumes. The preferred pH of the solution is from about 6 to 8. Amuch higher pH can be used.

Surface active agents, water repellents, and other textile treatingagents may be incorporated into the aqueous or emulsion treating mediato modify the treated textiles. Surface active softening agents improvetear strength of cotton and rayon fabrics.

The process of this invention can suitably be used to reduce thecombustibility of substantially any hydrophilic fibrous material such ascotton, rayon such as viscose rayon, ramie, jute, wool, paper, cardboardand the like materials which can be impregnated with a liquid and driedor cured.

Where a textile is being impregnated, it is of advantage to removeexcess impregnating liquor by passing the textile through squeeze rollsprior to drying or curing the impregnated textile. It is alsoadvantageous to dry the textile at about 70 to C. before it is cured ata temperature of from about 100 to C.

V The degree of flame resistance imparted to a textile by thesephosphorus and nitrogen containing resins can be varied from a lowdegree to a very high degree by varying the amount of polymer put in thetextile.

Some advantages of fiameproofing textiles in accordance with thisinvention are: textiles treated by this procods were used to demonstrateflame resistance of fabrics provided by this invention:

(l) The vertical flame test as described in US. Federal Service, FederalSpecification CCC-T-19lb (1951). In this test, a strip of cloth isexposed to the luminous flame of a Bunsen burner and flameproofness isjudged by the length of a tear produced through the charred area by astandard weight. The results of this test are expressed in char lengthin inches.

(2) The strip flame test as described in Textile Research Journal,volume 23, page 529 (1953). In this test, the degree of flame resistanceis measured by determining the angle at which a narrow strip of clothwill not continue to burn when held in the vertical position and ignitedat the bottom and then slowly rotating the cloth until the flame goesout. The greater the angle at which the flame goes out the greater thedegree of flame resistance. degrees represents the highest degree offlame resistance.

P i "oxide, 12.5% tetrakis(hydroxymethyl)phosphonium chlo- "ride, 4.0%triethanolamine and 1.5% cationic softener. "The solution was applied to8.2 oz. cotton twill in a T: EXAMPLE 1 An aqueous solution was made bydissolving parts (by weight) of. tris(l-aziridinyDphosphine sulfide, and5 parts (by weight) of tetrakis(hydroxymethyl)phosphoniurn. chloride in40 parts of water. The solution was then divided into four equal parts(A, B, C, and vD.) and treated as described below. A was allowed toremain atipH 5.1. The pH ofB, C and D was adjusted with tr-ibthanolamineto 6.1, 7.1 and 7.9 respectively. Someof eachsolution, A, B, C, and Dwas placed in a watch glass and then placed upon a steam bath for 15minutes. At .this time sample D wasa hard clear mass, C was a tough massand samples A'and B were very viscous liquids. After an additional '15minutes on the steam bath samples B, -C and D were hardpolym'erswhereas-A was a very tough mass.

Samples A, B, C, and'D (previously heated for :30 minutes'on steam bath)were placed in oven'at 140 C. for 5 minutes. PolymerA was light brownand water soluble. B was yellowish brown and was insoluble in water andacetone. Polymers C and D were'also insoluble in water and in acetoneand were light yellow in color. All samples were highly flame resistantand contained phosphorus, sulfur and nitrogen.

EXAMPLE 2 An aqueous solution was made containing 2.5 parts .Of, tris(1-aziridinyl)phosphine sulfide, "2.5 parts of tris-.(hydroxymethyl)phosphine oxide and '20 parts of water. The pH of thesolution was 5.1. It was divided into two equal parts, A and B and-thenpart B was adjusted to a pH-of 9.0 with triethanolamine. A part of eachsample was placed upon a watch glass and'heated on steam cone for 90minutes. both cases. They were then heated for 5 minutes at 140 C. Lightyellow tough polymers formed that were insolublein water and in ethanol.

When some of solutions A and B were placed directly in an oven at 140C., without prior heating on the steam bath, sample A decomposed withthe formation of dense white fumes.

EXAMPLE 3 An aqueous solution was made containing 6 parts oftris(l-aziridinyDphosphine oxide, 4.8 parts oftris(hydroxymethyDphosphine oxide and 43 parts of water and :thensuflicient sodium carbonate was added to raise the pH to 8.2. Most ofthe water was evaporated under reducedp'ressu're and then theviscous'liquid' was heated 'on steam bath for 100 minutes. The-productbecame insoluble in boiling water. The resulting material was heated for30 minutes at 110 C. in oven to produce a hard, clear polymer. It waspulverized and washed with water and then with acetone. The washedpolymer contained phosphorus and nitrogen and was flame resistant.

EXAMPLE 4 I *An aqueous solution with a pH of 60-65 was pre containing12.5 tris( l-aziridinyl) phosphine padder to awet pick-up of 56-58%. Thefabric was Viscous colorless polymers formed in I 6 dried for 3 minutesat C. and "then' portions of it were heated for 5 "minutes at varioustemperatures. After-curing, the samples were washedand dried. Testresults before and after a three hour soap-sodium carbonate boil areshown in Table I below. The treated fabric wasnot only flame resistantbut also glow resistant.

' Table 1 Tear Strength Breaking Char Length Elmendorf Strength (inches)Curing Resin (warp) Strip (Warp) Temp., Add-on, .Strength Strength 0.Percent retained, retained, Before After Percent Percent soap soap boilboil 6. 7 180 89, 4. 4 2 BEL .8. 8 .160 86 4. 1 BEL 10. 2 155 .88 3. 94. 6 11. 3 86 3. 7 412 11. 6 90 86 4. 3 4.4

1 Strength retained is based upon an untreated control fabric. 1BELmeansthat the strip burned entire length.

As shown in Table I the products showed excellent flame-resistance withas low as 6.7% resin add-on. Samples cured above C. and containing over10% resin showed excellent flame resistance and no afterglow after thestrenuous three-hour soap boil previously described. The hand andappearance of the fabric was substantially unaltered by the resintreatment.

EXAMPLE '6 Anothersample of 8 oz. cotton twill wastreated as describedin Example 5 except that the treating solution contained 4%triethanolamine plus 15% tris(l-aziridinyl) phosphine oxide [(CH N] P=O,15 tetrakis(hydroxymethyl) phosphonium chloride (HOCH PCl. The wetpickup was 60% and the fabric was cured at 150C. for tfive minutes afterdrying. The treated fabric contained 14% resin add-on, it had a charlength of 3.6 inches, and had a tear strength 20% greater than anuntreated control fabric as determined by the Ehnendorf test method. Ithad an excellent hand and was highly flame and glow resistant.

EXAMPLE 7 8 02. cotton twill was treated as described in Example "6'except that the treating solution contained 4% triethanolamine, 20%tris(1-aziridinyl)phosphine oxide and 20%tetrakis(hydroxymethyl)phosphonium chloride. The treated fabriccontained 22.6% resin after drying, curing and washing and had a charlength of 2.8 inches.

EXAMPLE 8 EXAMPLE 9 8.2 oz. cotton fabric was'paddedthrough an aqueoussolution (pH of 5.9) containing 16% tris(l-aziridinyl)droxymethyDphosphonium chloride, 4% triethanolamine, and 1.0% TritonX-100 (a wetting agent). The fabric was given two dips and two nipsthrough the solution 7 and the squeeze rolls of the padder were set togive a tight squeeze.- The fabric was dried for 4 minutes at 80 to 90 C.and then cured 5 minutes at C., and finally washed and dried. Itcontained--l5.5% resin addon and 1.55% nitrogen, 1.45% phosphorus and1.23%

EXAMPLE A sample of 8 oz. cotton sateen fabric was padded in an aqueoussolution containing 16.5% tris(1-aziridinyl) phosphine sulfide, 16.5%tetrakis(hydroxymethyDphosphonium chloride, 4% triethanolamine and 1% ofa wetting agent and then dried for 4 minutes at 80 to 90 C. The dryfabric was then cut into four pieces and then each piece was cured forfive minutes at the tom-i perature shown in Table H. The resin add-onobtained and certain physical data are also shown in Table II.

After the fabrics were cured, washed and dried, a portion of each of thefour samples was softened with Triton X-400 by padding it through anaqueous suspension of the softener and then drying.

l Elmendort tear strength of untreated control fabric was 11.9 lbs.

EXAMPLE l1 Two fabric treating solutions were prepared as follows:

" (A) An aqueous solution was made by dissolving 10 parts oftris(1-aziridinyl)phosphine sulfide, 10 parts oftris(hydroxymethyl)phosphine oxide in 80 parts of water and thenadjusting the pH of the solution to 7-8 by use of sodium carbonatesolution (this solution designated solution A); (B) An aqueous solutionwas made by dissolving parts of tris(l-aziridinyl)phosphine sulfide, 15parts oftris(hydroxymethyl)phosphine oxide in 70 parts of water and thenadjusting the pH to 6.4 by use of sodium carbonate solution (thissolution designated solution B).

A sample of sateen fabric that was padded in solution A, dried at 70 C.,cured at 150 C. and washed contained 6% resin. Another sample of sateenthat was passed through solution B, dried at 70 C., cured at 150 C. andwashed contained 6.3% resin. Both fabrics were flame resistant, werestrong and had a good hand.

EXAMPLE 12 Each solution contained a total concentration of reagents(APS plus THPC) equal to of the total solution weight. A fabric samplewas padded in each of the solutions, dried, cured 5 minutes at 150 C.and then washed and dried. The resin add-on obtained and the Elmendorftear strength (after softening with a cationic textile softeuer TritonX400) are shown in Table III.

Table III Moles of Reagent Elmendort' Solution in Solution Resin earChar Length N0. Add-on, (warp), (inches) Percent lbs. APS 'IHPC 1 1 6. 710. 1 6.3 1 2 4. 4 8. 5 BEL 1 3 2. 9 7. 3 BEL 1 4 2.3 6.3 Y BEL 2 1 7. 210. 3 BEL 1 (4.9) 3 1 6. 2 10. 2 BEL 4 1 6. 6 9. 8 BEL (6.5)

1 BEL means sample burned entire length. 3 One of the two samples testedpassed the flame test. The solutions used above were allowed to stand aabout 27 C. for 24 hours then again used to treat similar fabricsamples. The results obtained with these fabrics were very similar tothose described above. This experiment'shows that the aqueous solutionsare suitable for use even after standing for 24 hours.

EXAMPLE 13 An aqueous solution was prepared containing 17%tris(1-aziridinyl)phosphine sulfide and 17%tetrakis(hydroxymethyl)phosphonium chloride. This solution was used totreat several fabrics by padding, drying, curing and then washing anddrying. The fibers used in the fabrics, the resin add-on, and the degreeof flame resistance are shown in Table IV. The flame resistance wasmeasured by determining the angle at which a strip of the fabric (5inches long and /2 inch wide) would not continue to burn when held inthe vertical position and ignited at the bottom and then slowly rotateduntil the flame went out.

Table IV Flame RBSlStv ance Strip Resin Test (angle Fabric Treated(Fibers used in Fabric) Add-on, where strip Percent would not supportflame) degrees Cnttnn 15 180 Nylon 20 0 Cottonnylon 17 135 'Orlon 25 0Acetate rayon 10. 0 Viscose rayon 12 170 Cotton-viscose rayon 18 180Fortisan 1D 135 Cotton-fortisau- 17 .170

EXAMPLE 14 then washed and dried. Both the wool and paper were extremelyflame resistant.

In the foregoing examples the equal parts by weight of aziridinylcompound and methylol-phosphorus compound correspond, in molarterminology, to about 1 /2 moles of aziridinyl compound per mole ofmethylol-phosphorus compound.

We claim:

1. A process for rendering a hydrophilic fibrous organi fabric flameresistant which comprises impregnating such fabric with a compositionwhich comprises an aqueous solution containing (1) an aziridinylcompound selected from the group consisting of tris (i-aziridinyl)phosphine oxide and tris (l-aziridinyl) phosphine sulfideand v(2) amethylol phosphorus compound selected from the group consisting of tris(hydroxymethyl) phosphine oxide, tetrakis (hydroxymethyl) phosphoniumchloride, and a reaction product of said methylol phosphorus compoundwith a compound containing at least one trivalent nitrogen 9 atom and atleast one member of the group consisting of H-- and CH H attached to atrivalent nitrogen atom, said solution containing about from 1 to 1 /2moles of aziridinyl compound per mole of phosphorus compound, drying theimpregnated fabric, and then heating it at a temperature of about from100 to 160 C. for a period of about from 2 to minutes, using the longertime with the lower temperature to cause said aziridinyl compound andsaid phosphorus compound to react with each other to form aflame-retardant polymeric reaction product in said fabric.

2. The process of claim 1 in which the aqueous solution comprises asolution of tris (l-aziridinyl) phosphine oxide and tetrakis(hydroxymethyl) phosphonium chloride.

3. The process of claim 1 in which the aqueous solution comprises asolution of tris (l-aziridinyl) phosphine sulfide and tetrakis(hydroxymethyl) phosphonium chloride.

4. The process of claim 1 in which the aqueous solution comprises asolution of tris l-aziridinyl) phosphine sulfide, tetrakis(hydroxymethyl) phosphonium chloride, triethanolamine, andmethylolmelamine. v

5. The process of claim 1 in which the aqueous solution comprises asolution of tris (1-aziridinyl) phosphine oxide, tetrakis (hydoxymethyl)phosphonium chloride, triethanolamine, and urea.

6. Theprocess of claim 1 in which the aqueous solution comprises asolution of tris (l-aziridinyl) phosphine sulfide and tris(hydroxymethyl) phosphine oxide.

7. A process for rendering a hydrophilic fibrous organic fabric flameresistant which comprises impregnating said fabric with a homogeneousliquid composition containing the partially polymerized reaction productobtained by gently heating an aqueous solution containing (1) anaziridinyl compound selected from the group consisting of tris(l-aziridinyl) phosphine oxide and tris (l-aziridinyl) phosphine sulfideand (2) a methylol phosphorus compound selected from the groupconsisting of tris (hydroxymethyl) phosphine oxide, tetrakis(hydroxymethyl) phosphonium chloride, and a reaction product of saidmethylol phosphorus compound with a compound containing at least onetrivalent nitrogen atom and at least one member of the group consistingof I-I and -CH OH attached to a trivalent nitrogen atom, said solutioncontaining about from 1 to 1 /2 moles of aziridinyl compound per mole ofphosphorus compound, and then thermally completing the polymerization ofthe partial polymer in the fabric to produce in said fabric aflameretardant polymeric reaction product between said aziridinylcompound and said phosphorus compound.

8. A flame resistant, glow resistant, mildew and rot resistant, shrinkresistant hydrophilic fibrous organic fabric comprising such a fabricimpregnated with a polymeric reaction product of an aziridinyl compoundwith a methylol-phosphorus compound produced by heating a mixturecomprising (1) an aziridinyl compound selected from the group consistingof tris (l-aziridinyl) phosphine oxide and tris (l-aziridinyl) prosphinesulfide and (2) a methylol phosphorus compound selected from the groupconsisting of tris (hydroxymethyl) phosphine oxide, tetrakis(hydroxymethyl) phosphonium chloride, and a reaction product of saidmethylol phosphorus compound with a compound containing at least onetrivalent nitrogen atom and at least one member of the group consistingof H and -CH OH attached to a trivalent nitrogen atom, said mixturecontaining about from 1 to 1 /2 moles of aziridinyl compound per mole ofphosphorus compound.

References Cited in the file of this patent UNITED STATES PATENTS2,606,901 Parker et a1 Aug. 12, 1952 2,654,738 Lecher et a1 Oct. 6, 19532,672,459 Kuh et a1. Mar. 16, 1954 2,781,281 Berger Feb. 12, 19572,810,701 Reeves et al. Oct. 22, 1957

1. A PROCESS FOR RENDERIONG A HYDROPHILIC FIBROUS ORGANIC FABRIC FLAMERESISTANT WHICH COMPRISES IMPREGNATING SUCH FABRIC WITH A COMPOSITIONWHICH COMPRISES AN AQUEOUS SOLUTION CONTAINING (1) AN AZIRIDINYLCOMPOUND SELECTED FROM THE GROUP CONSISTING OF TRIS (1-AZIRIDINYL)PHOSPHINE OXIDE AND TRIS (1-AZIRIDINYL) PHOSPHINE SULFIDE AND (2) AMETHYLOL PHOSPHORUS COMPOUND SELECTED FROM THE GROUP CONSISTING OF TRIS(HYDROXYMETHYL) PHOSPHINE OXIDE, TETRAKIS (HYDROXYMETHYL) PHOSPHONIUMCHLORIDE, AND A REACTION PRODUCT OF SAID METHYLOL PHOSPHORUS COMPOUNDWITH A COMPOUND CONTAINING AT LEAST ONE TRIVALENT NITROGEN ATOM AND ATLEAST ONE MEMBER OF THE GROUP CONSISTING OF H- AND -CH2OH ATTACHED TO ATRIVALENT NITROGEN ATOM SAID SOLUTION CONTAINING ABOUT FROM 1 TO 1 1/2MOLES OF AZIRIDINYL COMPOUND PER MOLE OF PHOSHOROUS COMPOUND DRYING THEIMPREGNATED FABRIC, AND THEN HEATING IT AT A TEMPERATURE OF ABOUT FROM100* TO 160* C. FOR A PERIOD OF ABOUT FROM 2 TO 10 MINUTES, USING THELONGER TIME WITH THE LOWER TEMPERATURE TO CAUDE SAID AZIRIDINYL COMPOUNDAND SAID PHOSPHOROUS COMPOUND TO REACT WITH EACH OTHER TO FORM AFLAME-RETARDANT POLYMERIC REACTION PRODUCT IN SAID FABRIC.